This project focuses upon the different clinical forms of leishmanial infections in humans, immune responses to the parasite with particular references to cell-mediated response and the cytokine regulation of these responses, and characteristics of the causative parasites. Ten patients were referred to NIH for suspected leishmaniasis. Seven were U.S. Peace Corps volunteers or tourists, and two were military personnel, one of whom had been in the Persian Gulf region and was suspected of having visceralizing leishmaniasis. The other military case had proven visceral leishmaniasis acquired in southern Spain. One patient was a foreign service officer with an undiagnosed illness. Seven of these patients were treated with Pentostam (sodium stibogluconate) at the Clinical Center. The double-blind, placebo-controlled trial of topical treatment with paromomycin of atypical, nonulcerating cutaneous leishmaniasis in Honduras was completed. A total of 53 patients were enrolled in the trial, but the topical paromomycin as clearly not effective. One surprising outcome of the study was the finding that more than half of the 26 cases from one rural locality were caused by L. mexicana species rather than exclusively due to L.d. chagasi, as had been found previously. Collaborative studies with Dr. Sundar at Banares Hindu University in India were initiated on patients with visceral leishmaniasis. The object of the studies is to examine the cytokine response of bone marrow in patients with active visceral disease. Additional isolates of parasites from kala azar cases are also desired since L. tropica species instead of the expected L. donovani was recently found as the cause of disease in some instances.